Knocking then stall - now won't start at all

[mbrassart]

Thanks for the link.

It used to be my daily driver, but since I had places to go for the last 14 days, I had to get a new communter and make this a project car.

I can't wait to get it running again.

I may skip the leak down test and just pull the cylinder head.  I'm going to have to do that at some point anyhow, maybe I'll just open it up and see what I'm dealing with.

I was already looking at the salvage yards and craigslist for a donor car.  There was a 79 300SD for $700 last week, but I passed because I still didn't know what the problem was with mine, and didn't really want a second broke Mercedes in the driveway.

Much of this depends what I find, but I'm going back and forth between just repairing what I need to in order to get by, or do I want to do a complete engine rebuild.  This is all new territory to me, so I'm going to learn a lot either way.  Since I don't need the car running in a hurry, I may just have fun and, as we say in the Navy, "strip it down to parade rest."

I'll keep you all posted as I discover, and take pictures along the way.

Matt

[ponton]

If I were you, I would pull the engine, pop the head off and see where the damage was.  If it is the headgasket you will see lines where fluids have gone or a crack.  Fill the bore of the cylinders with a little bit of fluid and the combustion chambers in the head (with the valves closed) and see where the fluid leaks out.  Figure the cost of repair and decide whether to fix it or get a tested used engine.  I am still wondering though why it decided now was the time to not start.

Ian

[mbrassart]

It used to be my daily driver, but since I had to get places daily for the last 15 days, I had to get another car.  The good news is, now I can take my time and pretty much do whatever I want.

I'm going to skip the leak down test and remove the cylinder head so I can see what I'm dealing with.

I'm stuck already - I can't figure out how to remove the timing chain.  The Chiltons and the service manual are a little vague, and I can't visualize what is what.

It looks like I need to remove the three bolts marked to remove the timing chain - is that correct?

What is the red one?  It looks like an allen bolt, but none of mine seem to fit, and I don't want to force a square peg into the round hole.



I have a three day weekend coming up, and I can make some real progress...if I can make some progress.

Matt

[KenM]

Don't know about the diesel engine but WGB has written an excellent tutorial on replacing the timing chain on a M117, which can be found here if you do a search, might pay to go over that a few times, it seems like the kind of job where you want to be reasonably sure of the steps required and have all parts and tools on hand before embarking on the adventure I would say.

[mbrassart]

Thank you for pointing me to that post.  Much of it will not be applicable.  I checked the timing chain and I only have about 2 degrees offset between the timing marks on the camshaft and those on the crankshaft.  It appears that the chain is pretty new.

I got the rocker arms off today, and the camshaft is all loose except the connection to the timing chain sprocket.  Here is what I'm following in Chiltons:



I have done all these steps and am ready for this:



I can't figure out how to remove the gear from the camshaft.  Do I need a slide hammer to get it off?

Thanks,

Matt

[ponton]

Have you undone the chain tensioner?  It pushes on the left side chain tensioner.  To get the gear off use a gear puller http://www.harborfreight.com/catalogsearch/result?q=gear+puller they are cheap.  Its been a while since I did this and I only did it once.  You definitely need to take off the yellow. Try that and see if you can get the plastic guide out (gently) then see if you have to take off red or green.  I really can't remember.  I will take a look in my factory manual tonight if I remember.  Once you get that plastic guide out you can pop the gear off and wire tie the chain off to the side.

Ian

[koan]

I think you'll find the yellow pin has a tapped head, takes a metric threaded bit attached to a slide hammer to pull it out. Most here improvise with a bolt and nut  through a washer over an open ended spanner.

koan

[mbrassart]

I made a little progress yesterday.  I got the timing chain gear out and the rest of the camshaft.  I think I have all the linkages and obstructions moved to get the cylinder head off, but it's not budging...I guess I'll have to keep looking around.



Here is all the stuff laid out on a towel - I'm hoping by keeping things together, I'll remember how to put all this back together in the end.

[Big_Richard]

 on most engines theres usually a bolt or 2 hiding down the front of the cylinder head where the chain goes. make sure you have all of them out everywhere before using force to remove the head.

Looks like theres more disassembly required to remove that head to me...

[mbrassart]

Okay, there was definitely more to remove before the cylinder head would come loose.  I have everything off enough to wiggle the cylinder head, but one of the bolts for the timing chain guide (red one above) still needs to come off so that I can feed the chain down the hole as I lift the cylinder head off.

The good news is: I'm almost there.

The bad news is: I don't know if I'll ever get all this back together...lol.



I'll keep posting updates.

[mbrassart]

The good news is: it doesn't look like the head gasket.

The bad news is: it doesn't look like the head gasket.

If you look at the photos below, #3 and #4 piston heads are pretty chewed up.  It's no wonder they wouldn't hold compression.

Incidentally, unless you are an idiot like me, the cylinder head is really a two-man lift.  Lot's of Ibuprofin in my future.

What does the future hold for me (besides Ibuprofin)?  Can I replace the bad ones?  Should I just start rebuilding the engine?  I know many of you are going to say to "punt" but I think I'm committed to fixing her.  I just don't know how long it will take and how much it will cost.

#1 Cylinder



#2 Cylinder



#3 Cylinder



#4 Cylinder



#5 Cylinder

[mbrassart]

Does anyone know where I can find these pistons?  I'm going to start looking through the wrecking yards, but I wanted to see how much a new one would cost in the meantime.

Matt

[Big_Richard]

Its my understanding that the tolerances in diesel engines are a hell of a lot tighter than in gasoline engines. I very much doubt you could just swap the piston(s) from another engine into yours and expect a decent running engine.

I would think that new oversized pistons and suitably (professionally) machined bores will be required if you want to rebuild that bottom end. And even then god knows what else will be required...

A good condition second hand engine is a cheap way out, that thing is going to cost a lot of money to rebuild properly.

[TJ 450]

That doesn't look good at all... How was the engine running before it started running like it did?

Regardless, it needs a teardown/rebuild. Abnormal combustion perhaps?

Tim

[mbrassart]

That's the weird part - it was running very well.  Once I changed the glow plugs, I had no problems with hard or cold starts, and I was getting 30 MPG.  There were no problems until I had a problem - now it's a big problem.

Matt